GPU Processor limitation

hi,

i know that when it comes to games that the GPU is the main limiting factor, currently i've been looking at getting a dell xps 1730 (not prepared to wait around for alienwares m17x anymore with such a lack of info on it).

the config would be a Core 2 Duo Processor, 2.6Ghz with 6Mb L2 Cache, 4gb of ram, and 2 Nvidia 8800 GTX's in SLI.

now, i've read reviews on the GTX Sli's, which basically point out that when you have that much graphic-card power, the limiter in a system becomes the processor..

what i'd like to know is, is it worth having them if the processor is only a dual 2.6ghz core? the only faster option available is the 2.8ghz extremes, but that's an extra £500.. will i find that the 2.6ghz processors limit my speed too much to make it worth while?

at the moment dell has £200 off purchases on their UK site (not sure the minimum spend for it) but i can use that in conjunction with a 10% off voucher to get £400 off of the machine if i order today, which means my entire config with win XP and 2x160GB harddrives etc will come to about £1950 inc p&p, so i'm hoping that i can get some quick responses from more learned members of the forums ^^

 

If all you're going to do is play games, then the CPU will not bottleneck your experience, unless you make your games render in software mode. However, if you do that, then you are an idiot.

The thing that will bottleneck would probably be your HD.

 

hopefully by maxing out the ram available to my pc i'll avoid the HD delay as much as i possibley can ( though with the 32 bit memory limitations, i expect only to see about 2.5 ~ 2.9gb of that ram utilisable by the system).

the harddrives that come with the pc are RAID0(striping) 7200 RPM, that'd be enough to get some real use out of the cards, right?

 

Of course, RAID0 7200RPM HDs will bottleneck the system less, but they will most likely still be the slowest component on your machine when it comes to games. If you want the cream of the crop, you should be looking at Fibre Channel HDs (15000rpm+), although they will be incompatible with your notebook and will set you back an extra thousand dollars or so each.

However, for what you're doing, those specs will be more than enough to last you a few years (I would personally recommend you to just buy a desktop (XPS630 for example), which is about £1000 cheaper for those specs, and spend the rest of the money on a portable laptop (XPSM1330 for example), but I suppose you don't have much choice if you want to game on the go).

 

While it is true that the CPU has to send the GPU instructions on what to render, even with 8800 SLI's you shouldn't be bottlenecked by a 2.6 GHz Core 2 processor. CPU overhead for GPU functionality is fairly low thesedays, certainly low enough that you won't see a 2.6 GHz CPU preventing a top-of-the-line graphics combo in SLI from getting its instructions quickly enough.

The CPU can bottleneck some games, such as strategy games and games with large numbers of AI players, but you won't see your CPU bottlenecking primarily graphical games.

OK, time to get back to programming games that render graphics in software mode. Because I'm an idiot. Or I haven't yet bothered to learn how to do it in hardware mode and my graphics are sufficiently low-tech that they run fine in software mode. One of the two.

BTW, you'd probably be just as well off saving a few hundred and getting the T9300 (2.5 GHz) if it's an option. Maxing out is always tempting I know but the disconnect between performance gain and price is even worse here than it usually is.

 

That is definitly a good idea. And the desktop will have more longevitiy, and will be much easier and cheaper to upgrade down the road.

 

That system sounds pretty awesome to me. What would really make it perfect would be a quad core processor, but we won't be seeing those in a mobile platform till Summer 08.

I've always been wary of SLI/Crossfire due to the power increase/efficiency. But hey, if you know you will be playing graphically demanding games like Crysis and World in Conflict fairly often, it is the way to go.

For older titles, 1 8800m GTX is more than enough.

 

You could also get a SSD (Solid State Drive) for your XPS... that's the best it can get, for sure! This thing is fast as hell! Faster than ANY ordinary HD in the world...

Dell (US) actually offers it as an avaliable option for the XPS line... But dunno if they offer it in UK as well...

SO, if it's the HD the bottleneck, buy a SSD and you can already consider your problem solved!

 

The only time the hard drive is going to come into play during games is when the levels are loading. That's it. In-game it doesn't matter.

I assume you're looking at the T9500 processor - that's not worth it at all . . . stick with the T9300. It's significantly cheaper and you will not notice the difference between the two.

No matter what, the hard drive is going to be the bottleneck for overall system performance. Even if you install an SSD, there is no way getting around it. The hard drive is roughly 1000x slower than the next-slowest component in the computer, which is memory (and no, adding faster memory isn't possible and wouldn't help anyway).
Don't go for RAID 0, it's unsafe (double the risk of data loss since you are depending on two hard drives) and has little to no everyday performance improvement (somewhere around 3% improvement). It is only useful in specialized situations.

Bottom line - don't bother with the T9500, get a T9300 instead.

 

hi again,

i know i'm paying twice as much to have a laptop over a desktop, but i'm unable to have a desktop due to space/size, plus i need it to take to lan parties / move it between two spots on a weekly basis, and to set up a desktop with monitor and all the other stuff etc like that is unpractical.

the model i picked on the Dell UK site comes with 2x160 GB hdd's or 2x200GB hdd's already set in RAID0, i figure once i get it i may/maynot delete the RAID array and have them work seperately when i reinstall windows without all the bloatware etc that comes with it.

took your advice and opted for the 2.5Ghz processor, saving me about £250.

in total with the 3 years premium warranty, Windows XP etc it's totalled around abouts £2,050 inc p&p/vat, estimated delivery date 15th April.

now all i have to do is wait ^.^

ty for all the replies.

~GW

 

Probably it's a bit late, but here are some comparisons of Penryn game performance with different CPU clock speeds. Please note that numbers are for a single-8800m gtx notebook